<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
    <title>Three.js - Game - Load Models</title>
    <style>
    html, body {
        margin: 0;
        height: 100%;
    }
    #c {
        width: 100%;
        height: 100%;
        display: block;
    }
    #loading {
      position: absolute;
      left: 0;
      top: 0;
      width: 100%;
      height: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
      font-size: xx-large;
      font-family: sans-serif;
        }
    #loading>div>div {
      padding: 2px;
    }
    .progress {
      width: 50vw;
      border: 1px solid black;
    }
    #progressbar {
      width: 0%;
      transition: width ease-out .5s;
      height: 1em;
      background-color: #888;
      background-image: linear-gradient(
        -45deg,
        rgba(255, 255, 255, .5) 25%,
        transparent 25%,
        transparent 50%,
        rgba(255, 255, 255, .5) 50%,
        rgba(255, 255, 255, .5) 75%,
        transparent 75%,
        transparent
      );
      background-size: 50px 50px;
      animation: progressanim 2s linear infinite;
    }

    @keyframes progressanim {
      0% {
        background-position: 50px 50px;
      }
      100% {
        background-position: 0 0;
      }
    }
    </style>
  </head>
  <body>
    <canvas id="c"></canvas>
    <div id="loading">
      <div>
        <div>...loading...</div>
        <div class="progress"><div id="progressbar"></div></div>
      </div>
    </div>
  </body>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>

<script type="importmap">
{
  "imports": {
    "three": "../../build/three.module.js",
    "three/addons/": "../../examples/jsm/"
  }
}
</script>

<script type="module">
import * as THREE from 'three';
import {OrbitControls} from 'three/addons/controls/OrbitControls.js';
import {GLTFLoader} from 'three/addons/loaders/GLTFLoader.js';
import * as SkeletonUtils from 'three/addons/utils/SkeletonUtils.js';

function main() {
  const canvas = document.querySelector('#c');
  const renderer = new THREE.WebGLRenderer({canvas});
  renderer.outputEncoding = THREE.sRGBEncoding;

  const fov = 45;
  const aspect = 2;  // the canvas default
  const near = 0.1;
  const far = 100;
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.set(0, 20, 40);

  const controls = new OrbitControls(camera, canvas);
  controls.target.set(0, 5, 0);
  controls.update();

  const scene = new THREE.Scene();
  scene.background = new THREE.Color('white');

  function addLight(...pos) {
    const color = 0xFFFFFF;
    const intensity = 0.8;
    const light = new THREE.DirectionalLight(color, intensity);
    light.position.set(...pos);
    scene.add(light);
    scene.add(light.target);
  }
  addLight(5, 5, 2);
  addLight(-5, 5, 5);

  const manager = new THREE.LoadingManager();
  manager.onLoad = init;

  const progressbarElem = document.querySelector('#progressbar');
  manager.onProgress = (url, itemsLoaded, itemsTotal) => {
    progressbarElem.style.width = `${itemsLoaded / itemsTotal * 100 | 0}%`;
  };

  const models = {
    pig:    { url: 'resources/models/animals/Pig.gltf' },
    cow:    { url: 'resources/models/animals/Cow.gltf' },
    llama:  { url: 'resources/models/animals/Llama.gltf' },
    pug:    { url: 'resources/models/animals/Pug.gltf' },
    sheep:  { url: 'resources/models/animals/Sheep.gltf' },
    zebra:  { url: 'resources/models/animals/Zebra.gltf' },
    horse:  { url: 'resources/models/animals/Horse.gltf' },
    knight: { url: 'resources/models/knight/KnightCharacter.gltf' },
  };
  {
    const gltfLoader = new GLTFLoader(manager);
    for (const model of Object.values(models)) {
      gltfLoader.load(model.url, (gltf) => {
        model.gltf = gltf;
      });
    }
  }

  function prepModelsAndAnimations() {
    Object.values(models).forEach(model => {
      const animsByName = {};
      model.gltf.animations.forEach((clip) => {
        animsByName[clip.name] = clip;
      });
      model.animations = animsByName;
    });
  }

  const mixers = [];

  function init() {
    // hide the loading bar
    const loadingElem = document.querySelector('#loading');
    loadingElem.style.display = 'none';

    prepModelsAndAnimations();

    Object.values(models).forEach((model, ndx) => {
      const clonedScene = SkeletonUtils.clone(model.gltf.scene);
      const root = new THREE.Object3D();
      root.add(clonedScene);
      scene.add(root);
      root.position.x = (ndx - 3) * 3;

      const mixer = new THREE.AnimationMixer(clonedScene);
      const firstClip = Object.values(model.animations)[0];
      const action = mixer.clipAction(firstClip);
      action.play();
      mixers.push(mixer);
    });
  }

  function resizeRendererToDisplaySize(renderer) {
    const canvas = renderer.domElement;
    const width = canvas.clientWidth;
    const height = canvas.clientHeight;
    const needResize = canvas.width !== width || canvas.height !== height;
    if (needResize) {
      renderer.setSize(width, height, false);
    }
    return needResize;
  }

  let then = 0;
  function render(now) {
    now *= 0.001;  // convert to seconds
    const deltaTime = now - then;
    then = now;

    if (resizeRendererToDisplaySize(renderer)) {
      const canvas = renderer.domElement;
      camera.aspect = canvas.clientWidth / canvas.clientHeight;
      camera.updateProjectionMatrix();
    }

    for (const mixer of mixers) {
      mixer.update(deltaTime);
    }

    renderer.render(scene, camera);

    requestAnimationFrame(render);
  }

  requestAnimationFrame(render);
}

main();
</script>
</html>
